Requirements for enhanced characteristics and lighter and more compact features of electronic equipments in recent years promote high-density integration and high-density installation of electronic components such as semiconductor packages and the like, and miniaturization and high pin count of such electronic components are progressing. A solder joint is employed for obtaining electric coupling for the electronic components, and for example, it is employed for a conducting junction between semiconductor chips, a conducting junction between a semiconductor chip and a circuit board such as such as a package having a flip-chip device installed therein, a conducting junction between a circuit board and a circuit board. Further, requirements for reduced thickness, miniaturization, fine-pitch junction for electronic component promotes a proposal, in which an underfill material is supplied in a solder joint by utilizing capillary phenomenon and then the joint is reinforced to ensure reliability of the junction.
When a gap generated by a solder joint is reinforced with a resin such as an underfill material, a use of the resin at a quantity, which is larger than a volume of a space formed by the gap to be filled, may cause an excessive resin effusing over unwanted locations, causing, for example a pollution of a device or reducing an dimensional area of a terminal available for installing other components due to the effused resin. Further, the approach for employing the underfill material utilizing capillary phenomenon requires a number of operations for stuffing with the underfill material, which leads to one of the reasons for increasing the production cost. Thus, an approach is proposed in the process for coupling the semiconductor element to the substrate, including dropping a mixture of an underfill material with a flux, and then curing the underfill material simultaneously creating a solder-joint. Such assembly process is effective in providing significantly reducing the production cost since the operation for filling the underfill material is not required.
For example, Patent Document 1 describes a method for creating an interconnection of an electronic component with a substrate. Such method involves disposing a binding material between a solder bump formed in the electronic component and a patterned metal formed in the substrate to provide a connection between the solder bump and the patterned metal. More specifically, first of all, the electronic component and the substrate are suitably aligned so that the patterned metal having a coating of the binding material faces the solder bump. Subsequently, a vacuum press apparatus is employed, and the solder bump is approached to and abutted to the patterned metal and then is squashed until the solder bump is deformed to compressively bond thereof. The binding material is eliminated in this process from the contact point between the solder bump and the patterned metal. Then, a reflow process is conducted to provide a junction between the solder bump and the patterned metal, and the adhesive agent is cured to provide a connection between the electronic component and the substrate.
[Patent Document 1]
    Japanese Patent Laid-Open No. H04-280,443